About 12 percent of women (7.3 million) in the United States aged 15-44 had difficulty getting pregnant or carrying a baby to term in 2002, according to the National Center for Health Statistics of the Centers for Disease Control and Prevention. In one third of cases, infertility is due to the man (male factors). Major etiological factors include ovulatory dysfunction, abnormal tubal function, cervical factors, and male sperm factors. (The Merck Manual of Diagnosis and Therapy, Merck Research Laboratories, 16th Ed., p. 1768-1770, (1992)). An estimated five to six percent of men in the reproductive age group are infertile. Most causes of male infertility are due to an abnormal sperm count or low semen quality.
A majority of problems associated with fertility in males stem from changes in testosterone levels. In particular, decreases in concentration of this steroid can result in infertility and impotence. Endogenous estrogen has been well-documented to serve as a regulatory factor in testosterone production by interaction with the estrogen receptor (Nozu, K. et al., J. Biol. Chem. 256, 1915 (1981); Brinkman, A. et al., Endocrinology, 110, 1834 (1982)). Unfortunately, hormone therapies can have serious side-effects.
Thus, it is an object of the invention to provide non-steroidal compositions and methods for treating male infertility.
It is another object of the invention to provide compositions and methods for decreasing sperm concentration in semen.